title: Sensitivity of MRI for directly detecting neuronal electrical activities in rat brain slices.
abstract: We developed an experimental setup for magnetic resonance imaging (MRI) of rat brain slices maintained in a hemoglobin-free medium and showed that the MRI system has a sensitivity to magnetic fields of 10(-11) T. The originally developed non-magnetic sample holder consisted of a microelectrode array for recording neuronal potentials and perfusing channels for the medium. Because of the hemoglobin-free condition, the magnetic fields could be distinguished from the baseline signal fluctuations due to hemoglobin. A theoretical estimation of the signal-to-noise ratio showed a sensitivity of 3.3 × 10(-10) T. Parameter optimization using a 7-T MRI system with the developed sample holder resulted in an experimental sensitivity of 4.0 × 10(-10) T. These MRI sensitivities potentially enable us to detect weak magnetic fields arising from neuronal activities, and are sufficiently high for detecting neuronal magnetic fields of 1.4 × 10(-11) T generated in rat brain slices by averaging signals 810 times.
authors.forename: Dongmin
authors.initials: D
authors.lastname: Kim
authors.forename: Takao
authors.initials: T
authors.lastname: Someya
authors.forename: Masaki
authors.initials: M
authors.lastname: Sekino
mesh_terms: D000818:Animals; D017352:Echo-Planar Imaging; D004558:Electric Stimulation; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D066298:In Vitro Techniques; D008279:Magnetic Resonance Imaging; D008839:Microelectrodes; D008962:Models, Theoretical; D009474:Neurons / Q000502:physiology*; D051381:Rats; D059629:Signal-To-Noise Ratio